package exercise;
import java.util.*;
public class TestDemo10{
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		int num = scan.nextInt();
		int rel = faibonaci(num);
		System.out.println("rel = "+rel);
	
	}
	public static int fabinaci(int n){
		int i = 0;
		int f1 = 1;
		int f2 = 2;
		int f3 = 1;
		for(i = 3; i <= n; i++){
			f3 = f1 + f2;
			f1 = f2;
			f2 = f1;
		}
		return f3;
	}





	public static void main5(String[] args){
		Scanner scan = new Scanner(System.in);
		int num = scan.nextInt();
		int rel = faibonaci(num);
		System.out.println("rel = "+rel);
	}
	public static int faibonaci(int n){
		if(n == 1 || n == 2){
			return 1;
		}else{
			return faibonaci(n -1) + faibonaci(n - 2);
		}
	}




	public static void main4(String[] args){
		Scanner scan = new Scanner(System.in);
		int num = scan.nextInt();
		int sum = get_bitSum(num);
		System.out.println("sum = "+sum);
	}
	public static int get_bitSum(int num){
		if(num > 9){
			return num%10+get_bitSum(num/10);
		}else{
			return num;
		}
	
	}




	public static void main3(String[] args){
		Scanner scan = new Scanner(System.in);
		int num2 = scan.nextInt();
		int sum  = add(num2);
		System.out.println("sum = "+sum);
	}
	public static int add(int num2){
		if(num2 == 1){
			return 1;
		}else{
			return num2 + add(num2 - 1);
		}
	}




	public static void main2(String[] args){
		Scanner scan = new Scanner(System.in);
		int num1 = scan.nextInt();
		fun(num1);
	}
	public static void fun(int num){
		if(num > 9){
			fun(num / 10);
		}
		System.out.println(num % 10);
	}





	public static void main1(String[] args){
		Scanner scan = new Scanner(System.in);
		int num = scan.nextInt();
		int ret = mulLoop(num);
		System.out.println("ret = "+ret);
	}
	public static int mulLoop(int num){
		if(num == 1){
			return num;
		}else{
			return num * mulLoop(num - 1);
		}
	}
}